A man was arrested today over the murder of a pensioner who was stabbed after going to the aid of his neighbour - a convicted paedophile - during a robbery.
After the death of Graham Buck on Saturday, Hertfordshire Police appealed for help in tracing 55-year-old Ian John McLoughlin who they wanted to question in connection with the stabbing.
McLoughlin, also known as Ian John Baker, was arrested in London at around 1am and is being questioned on suspicion of murder and robbery, the force said.
Mr Buck, 66, received fatal stab wounds when he responded to cries from the home of 86-year-old Francis Cory-Wright in the village of Little Gaddesden, near Berkhamsted.
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